Call Us, M-F 7-6 PT

Blog

What is happening around us

At 4:00 am on December 16th, we weren’t sleeping. We were emailing back and forth in shock at the sudden probability of the ITC extension being signed into law.

We had high hopes for an extension, but didn’t expect it to get done so suddenly. The next day, after greeting each other with “Merry Solarmas,” we celebrated as any proper company would, with champagne and cake in the office kitchen. We explained the basics to our team, 5-year extension of the 30% federal tax credit, bonus depreciation extension, Section 179 made permanent.

I’ve looked at Enphase vs. SolarEdge before from the view of reliability and energy production. I also considered installation time, concluding that Enphase is superior due to not having to install a central inverter while SolarEdge does. The reality of the situation is somewhat different, so I’m revisiting this conversation with a much-needed update utilizing new information and perspective. My valuation focuses on three main points, installation time/labor, price of materials, and energy production.

The most popular microinverter and the most popular DC optimizer butt heads a lot in the current solar market. Both are panel-level MPP trackers that maximize individual panel yield. Both make the array more resistant to shading and panel mismatch. And both are fully compliant with the latest Rapid Shutdown requirements for solar systems.

When you install a system, sometimes you are asked to verify that it is producing the expected amount of power. Simply reading the inverter LCD screen will give you the AC power production, but that information hasn’t been checked against the site conditions so you have no way of knowing if it’s correct or not. To prove it using math, you have to perform a production analysis. I am going to go over the tools and methods to analyze a solar array for power production based on temperature and solar irradiance.

The mark of a good salesman is identifying customer needs and providing them the products they need to fulfill those needs. I’m taking a break from design posts to take a look at the sales side of solar and some of its unique challenges. I’ve enlisted the expertise of our resident sales guru, Tim McGivern. Tim is a seasoned veteran of sales with a firm grasp of customer interaction, and he comes with a wealth of knowledge and experience. Today’s challenge is how to sell quality and value versus pure cost in a solar project.

For today’s post, I brought out the solar modeling software and gotten myself into trouble (grid tied inverter loading analysis). System analysis and solar modeling software is a delicate subject, there are dozens of variables and different models can produce different results. I’ve tried to keep things as simple as possible for the purpose of this analysis.

When designing a solar system, the most important calculation is determining the length of the string of solar panels. Solar inverters and charge controllers have set voltage windows that have to be met by a string of solar panels whose voltage can vary as much as 40 – 60% throughout the year. With low string voltages, operation is less efficient and the system can be in danger of shutting off during hot conditions. Design a string voltage too high and cold sunny conditions could put the inverter into an overvoltage fault mode which shuts the inverter down. Solar designers have to hit the “sweet spot” where their string voltage will always fall within their equipment’s voltage window while maximizing the string length for more efficient operation. This is done by designing solar strings based on the upper voltage limit of the inverter or charge controller.

Much has changed in the solar PV industry in the past five years. Solar panel efficiency has grown incredibly while prices have dropped so much that incentives are hardly needed to make solar projects financially viable. New solar mounting technology allows for automatic grounding from the solar panel, with universal clamps and advanced ballasted and penetrating designs. However, by far the biggest advances have been in inverter technology. Inverter efficiency has steadily increased, voltage windows have gotten wider, and dual MPPT inputs are now a standard. By far the biggest advance has been the approval of a true 1000V DC voltage window. Coupled with dual MPPT inputs and a wide input voltage window, commercial system design is more flexible and adaptable than it has ever been.

The site analysis is a critical junction in the process of selling and installing a solar system. Proper information gathering leaves your installation team with everything they need to know to prepare for the install. Leave out the wrong piece of info and there could be last minute design changes, emergency trips for more equipment, and an overall lack of professionalism in the eyes of your customer. A good site analysis will give you all of your design information in an efficient and structured manner and leave a lasting impression on your customer.

Posts navigation

Recent Posts

Affordable Solar is committed to helping solar contractors grow their business by offering innovative financing and credit solutions, giving the best value on high quality solar energy system components, and providing business solutions that enable installers to increase their local market share.